Propeller mechanism



Nov. 14,1944. w. J. BLANCHARD' mL '2,362,444

PROPELLER MECHANI SM 8 Sheets-Shet 14 Filed Oct. 21. 1940 4M. www

Nov. 14, 1944. w` J, BLANCHARD 1 '|A| 2,362,444

PROPELLER MEcHANIsM Filed Oct. 2l. 1943 8 Sheets-Sheet 4 C24r/s 5J:fire/Verf MAM, ,www ,1- fm, y

NOV- 14, 19445 w.`J. BLANcHARb TAL- 2,362,444

` PROPE'LLER MEcHANIsM Filed am. 21. 194:0v s sheets-sheet 5 Nov. 14,19.44. l W. J. BLANCHARD Erm. 2,362,444

noPELLER MECHANISM Filed OG'b. 21, 1940 8 Sheets-Sheet 6 me/whomPRO-PELLER MECHANISMl n Filed oet. r21, 194e` a sheets-sheet 7 PROPELLERMECHANISM Filed Oct. 21. 1940 8 Sheets-Sheet' (j wue/wtou,

and'

Patented Nov. 14, 1944 frUNiTEfD STATES -v f, `v tessuto.PROPELI'JERMECHANISM i l r .f

Wel-neral. Blanchardand Charlesr S. J. MacNel, Dayton, Ohio, assignors,by mesme'astignnientsv to General IMotors Corporation, Detroib-Mich.,l

This invention relates'to'prop'ellers and'more particularlyto 'propellers*` of the tandem or dual rotation type.'

yIt `is the principal 4'object "of 'the invention `to provide apropeller comprising"twoy groups of propeller blades mountedeoaxially'and` driven oppositely 'to eachother in which provision is made foradjustingthe. pitch'ang'le setting 'of both groups o f'blades asdesired.

It isv a further object te'iprmride a. "propeller of 'this characterin'which the "pitch jof'ftlie two sets ef blades maybe "adjusted ywith af pred-eter- .a` corporation ofDelaware Applieatitnoetpber121, 1940,Asenti Naja-taillis @settima (atlete-135.6) t

tien; eertain ofthe partshein-'gshewn in elevationfahd others beingsectioned temere clearly show the constii'tion'thereof;

- iFig. 2` is va'transversesectionalvi'ew on the line 2:2 4Vof* Figgr;shutting the hydrauhe mechanism 'ofthe rear'hub;

' f igiiis a detailisectieiilview onthelineaf-s minedeiirerentiaisetting with Yrespect 'te ee-eh v'othersl'lchasto 'provide'fo'rtheutilizationby the 'rear propeller of 'energyfinthe slip'stre'am'from'f the vforward propeller tode v'elop'a maxiinu'n'r overall outputandefoiency.

It is also anobject to Aprovidesuehap'ropeller in'which separatesourcesof power are'provide'd for elTecting-adjustment of the pitch ofe'aollof the sets of propeller blades l'and arranged for propervconcurrent control', I

automatically.

It is a furtherobject to provide a separate source of `hydraulicoperating power for adjust'- ing the pitch of eaCho thesets'ofbla'de'sdispens-v ing with the .use of iiuitl pressuretransmitting connections'between relativlyinovable parts.v

It is a still further Lobject to provide a dual' rotation propellerassembly v*in 'Which'each of the propellers hasits'own' Vhy'draulioadjusting in'h# dependently 'controlled andthe other' controlleddependently in -accordance 'withthe 'position ocicupied by the rstsothat 'theftwo 'propellers aty all times occupy properrelative positions.

It is a further 'object to provide a dual frotaeither manuauy or`adjusting mechanism; y40' position in the e`ve'nt"of failure oftheadjusting or controlimechanism.

It is a stm further 'objectfte provideadiial rotation hydraulicallyadjustablepropeller 'a'sser'h-` bly inwhich "the pitc'hof -bothsets ofpropeller blades is easily'and rapidly adjustable over'a wide range "ofblade angles v'and-into a featheredfpositien. f yother `ehjeetsandadvantages win be apparent from the following 'descriptio'n,Vtneaccompanythe lfcirvvard hub;

Yortie. 2 shewingithepumpmeehahisfn; l

` "riep-"eis a iie'taiise'ttierrai-view eh'the'iihe t-t. -ef Fig.' l2showing' vthe "eenstriietieh e: the 'ae-- vbroken aw'alyt "Show "theConstrlitn thereof governor springs" ved speketethe Iiiiel l-'lilffif'igio;

' Fig. F12 gis a transverse se'tienta tiewshewiiig the adjustingmechanism eh the 1ihe iz-'fz 'ei- Fig. 1;

Fig `17fis a'view .pitiirijlitilly'i'in settien ythe.petrtiallt'7'elvatioilwith lthe. casing removed .from

Fig; 18 is", e firent Lei'evtihai tiet ieg the' for- Ward hub with apart; 'th'er'e'obei'ng brokenaway to show-the` operating mechanism forseouring im@ W5@ 'sectional 56h fthe line f "tail settie'nai geh the.iih'e tiehi view ehthe i'ihe the position of response of the forward hubwith respect to the rear hub; n

Fig. 20 is a partial detail view showing the manner in which theadjustment of the setting of the regulator valve in the forward hub issecured;

Fig. 21 is a schematic representation of the principles of control aspresent in this invention;

Figs. 22-24 are diagrammatic representations I y illustrative of themanner in which the regulation ofthe pitch setting of the forward hub isobtained; and f Fig. 25 is an elevational view on a smaller scale of theassembled dual rotation hub.

The invention relates to a dual rotation adjustable pitch propeller,that is one in which suitable drive mechanism is provided for operatinga forward hub in one direction and a rear hub at the same speed but inthe opposite direction. The blades carried by the respective hubs are-of opposite pitch so that the thrust produced by both sets of bladestakes place in the same direction. The two sets of blades are mounted intandem, and are arranged coaxially and relatively close together,ordinarily spaced apart adistance less than the radius of the blade, asshown for example in Fig. 25. It is found that such an arrangementresults in balanced reaction forces andin substantially increasedefficiencies particularly under high speed conditions and with highpitch settings of the blades.

In accordance with the present invention, the pitch angles of the bladesof both sets are adapted to be adjusted or varied in order to secure the'best results under all conditions of operation.

Provision is made for regulation of the assembly to a constant speedcondition under varying night conditions, and for the preselection of adesired speed to be maintained within the operating range of speeds,manually or under the control of instruments. The blades may be operatedand adjusted over a wide range of pitch settings varying from smallangles, or from a position of negative pitch if desired, up to highoperating angles and into a fully feathered position. Both sets ofblades are concurrently adjustable either to the same pitch or to apitch such that there is a predetermined differential in the setting ofthe two blades as found most desirable and such adjustments are effectedpositively and rapidly. Furthermore each hub assembly is complete initself, each incorporating its own hydraulic system, including pressuredeveloping, controlling, and applying mechanism. Thus there are norunning joints between relatively rotating parts through which fluidoperating pressure is required to be transmitted under pressure, and ahighly satisfactory construction and operation are thus secured.

The invention may be utilized in conjunction with various types ofadjusting mechanism for varying the pitch of the blades, and is notlimited to any particular arrangement for this purpose. It isparticularly adapted however for use in conjunction with the propellermechanism shown in applicants copending applications Serial Nos. 279,530and 279,531 led June 16, 1939, now U. S. Patents 2,307,101 and2,307,102. For purposes of illustration, the invention will behereinafter described as embodied in a propeller constructed generallyin accordance with said copending applications. y

Referring to the drawings which disclose a preferred embodiment of theinvention, there is shown an engine housing I from which there extendsan inner drive shaft II and an outer concentric drive shaft I2. Suitabletransmission mechanism is provided for driving these two shafts inopposite directions -and at the same speed, such mechanism not forming apart of the present invention and not being shown in the drawings,

The `rear or inner'hub indicated generally at I4 has a plurality ofblade sockets I5 associated therewith in which are mounted the propellerblades I6. As shown the hub comprises three such sockets and acorresponding number of blades, it being understood that any number ofblades and blade sockets may be provided as desired. The drive shaft I2and hub I4 are provided with cooperating spline parts 2U which providefor receiving and removing the hub in proper driving relation over theshaft. It is held in place thereon by a wedge ring 2I adapted to workagainst a tapered ring 22 at the inner end` of the shaft. A lock ring 23provides for retaining the ring 2l and the hub in assembled position.

The drive shaft I2 terminates within the confines of hub I4, while shaftII extends forwardly and receives thereon'the outer or forward hub 25.This hub is similarly provided with a number of blade sockets 26 shownas being the same number as provided for the rear hub, in which aremounted the several blades 21. The hub 25 and drive shaft II havecooperating spline portions 28 which provide for removably receiving thehub in operating position over the drive shaft. It is held in place by`means of wedge ring 30 working against a tapered ring 3| which isbacked by a nut 32 fastened upon the drive shaft. ring 30 is retained inplace by the forwardly projecting sleeve 35 in accordance with the usualpropeller construction. A locking pin 36 prevents relative rotationbetween the sleeve 35 and the drive shaft Il, and snap ring 31 receivedin a groove in hub 25 provides an abutment to facilitate removal of thehub from the shaft. A sheet metal housing section 38 is preferablyprovided over the forward nose of the `propeller to minimize windresistance and to enclose the end of the hollow drive shaft.l It will benoted that the inner drive shaft II is hollow, and offers no obstructionto the mounting of cannon or the like for firing through the hollowdrive shaft.

In order to afford proper supportfor the forwardly extending drive shaftI I, there is provided a roller bearing 40 having an inner race 4Icarried by the shaft II and held in place by nut 32 and an outer race 42kin supporting contact with the forwardly projecting portion 43 of theinner hub I4. In this Way proper alignment and support for the tworotatingl shafts is provided.

A substantial part of the mechanism for securing adjustment of thesetting of. the blades is the same in the two hubs, and accordinglyattention will be' directedl to the rearor inner hub, the' constructionof which will be described rst, and thereafter the differences inconstruction in the forward hub will be described.

Referring to Figs. 1` through'll,V the construction in vtheinner hubcomprises a radially extending -plate or casting 5I) which is carried byand rotatable 'with hub 14,- being removably held in place thereon by alocking ring 5I threadedly engaged upon the hub. Attached to the outerperiphery of plate 50 by means of bolts 52 is a casing or housing member53 which together with the plate 50 forms a reservoir for receiving aquantity of pressure operating fluid.

A stationary member 55 extends into the hous-@inwardlyonlitsgpressureistroke bythe-high points onthe .camendalternatelygpressed voutwardly on fing, :being boltedf ibycmeans. ofbolts'56-nto an adapter fplate: .51-connected to the engine casing or tosome suitable ,non-rotating zpart. ,It ais :formed with'r an axiallyextending sleevepart 58 located immediately youtwardly of :sleeve 5|-and f extending adjacent plate 50, and projecting radi- .allyoutwardlythereof it is formed withra cam member 59. 'The joints or points ofrunning con-A tactof the reservoir and this stationary member are sealedto prevent loss of fluid. For this pur- .pose 4a washer 60 'isprovided,"v which is held in .l

place against the adjacent surfaces of plate 50 `and sleeve 58bycompression spring 6 I, the Whole.l

being retained by aplate 62 .vboltedtothe inner 'surfaceofmember'50by'meansz0f bolts 53. vAt

" the ,point of contact of the casing553 with the stationary member 55,a similar sealing -joint indicated generallyat 64 isprovided, thusassuring the maintenance of an effectively sealed reservoir forcontaining the operating uid. f l r vIt is found at times thatunderoperating conits suction stroke by the springe. Provision is .made for;readyremoval zand replacement of ,the .spring bylmeansof .a movable cap88 threadedzinto the ihousingnportion'15;. andrihaving .a shankuBSthereon 'for f, V,guiding spring :186 ithereover, .the

springthusbeing. easily replaceable.

:The pressure chamberfil.; of .the .pump 'com vfmunicates ',directlylbypassage. 90a. .with the yinter- .mediate xchamber 9| ofthe. .valvevrmechanism 1.| .This .mechanismas shownfin Fig. 4 .also is:mountedvwithin theplate '50,.zand'comprises asuetion inletivalve 92umounted upon va central Aguide .pin Y93 Yand resiliently .urged towardclosed seating position. by;1neans .of spring.- 94. The 1 inletrpori-,is

ditions and the.--normally resultant increase in..

temperature, air which may have leaked intofthe t ties` passing into the.fluid system.

reservoir is subject to expansion and 'may produce a pressure increaseinthe reservoir. To repressure release in the form of a ball checkyvalve 66 resiliently urged toward seating Iposition by means of springB1. Escape of air under pressure is permitted' through this valve, butfluid `will not escape becauseunder co-nditions of operation .the iiuidis located at thel radially Vouter .-25 lieve such pressure increase,the` reservoir at a radially inner point thereof is provided with ashown at95 ,indirect communication with the ,reservoir .fand bl'eing"located radiallyoutwardly ,fthereof sothat it willbe assured ofreceivinga supply of the :fluid :from .the .reservoir during operation'.If., desirediia suitable protection device .may g be .located-over.; theinlet to :prevent impuri- An voutlet or discharge .valve 96 is mounted...upon fthe guide; pin 93 Vand .resiliently urged ltowardfseating:position `by vspring .9.1. Ity controls the discharge .fromrt-he pumpchamber 9| tothe .discharge chamber. L w* Aswillibe apparent from ytheabove the 'Opera- .tion of :.thepumpandfvalve mechanism is as follows.Upon the rotation ofthe hub and plate 50,

,the;pump iszcarried .around with respect to cam f `59, thus causingthe-'pumppiston to be 'alternately portion ofthe reservoir and henceexerts no pressure as such upon the relief valve. Upon cooling,

should the pressure within the reservoir fall below atmospheric, air mayseep into the samethroughthe sealed joints above described toequalizethe pressure. y

Withinthe reservoir there is located a selfcontained pressurekdeveloping-and controlling systemso that fluid pressurev is notrequired to be transmitted from' a stationary or non-rotating part. of.the propeller into the hub, and hence .no packed joints-operating underhigh kpressure conditions are required; -Pump mechanism is rlocatedwithin .the `housing* preferablyy comprising. afpair of pressure.developing.` pumps. These .pumpsare shownat 10, and-asillustratedinFig.2,y are suit- .ablyspaced from Veach other arcuately so lthat vthey willfunction invpredetermi'ned timed relation .to each other. rEach pump hasits ownasso.- ciat'ed valve mechanism 1 Land there is alsoassociatedtherewith acommon rrelief vvalve mechanis-m indicated generally at 12. t

Referring .now to the .l pumpV mechanism;` as shownin Fig. 55 the pumpisl mounted Withinathe plate .50, a suitable elongated chamber -15 beingintegrally iormedlin the `plate to receivethe pump. The pump piston `80is mounted for sliding movementv in a direction parallel with the axisof rota-f tion within .cylinder 8|. It carries at itsouter movedsinwardg-and .outward .with respect to its ,cyllnden Upon outwardmovement the pressure in the Valve chamber; 91| is reduced, therebyclost ing valve member 96,'and causing valve member 92 .to open to .drawfluid zthereinto.` Upon 'the return orpressure stroke of the pump, valvemem- 40 y. developed to afford proper operation, it is no longernecessary that the pump mechanism continuevto supply fluid underpressure, and its'continued operation would merely result in unnecessaryworking and heating of the fluid. In order tok relieve the action undersuch circumstances,

end a .cross-shaft. 82 havingarms 83. v.projecting therefrom which yareyguided in slots 84' formed within vthe outer end of the; cylinder 8|.:This

construction provides -for reciprocating movement of thepistonpreventing angular or twisting motion, thereof. Aeompressionspring Sli-.normally urges the ,pump piston outwardlyofl thek cylinder,and intosuchpositionthat roller :81, ,carried upon the .cross-shaft82,-r'juns incontinuous bearing :en-A

gagement withxed cam .59. -Thel'tcamispreferablyprovided with; two lobesor highpoints, such that lupon operationofthe hub and .with thev pumpthe vrelief valve 12 is provided. As shown, this valve isalsohjmountedwithin the plate` 50, and comprises a movable piston member |00Xhaving aland` |0| lthereonand a second land |02 of..

greater diameter. 'Theipiston is movable within aI cylinder |03 havingproper internal diameter *to receive the two lands therein. The cylinderis ported at v| 04 inthe range'of land I 0| and a connectiony |05 leadsthereinto from the valve cham- A second port |06 in the range" ofy land.|02 lis provided and lconnection |01 leads theret .and is preferably`apertured at its outer end as I into fromA the discharge lcl'xamber 98.;The interior'ofth valve |00 may be hollowA as shown shown at' |08 inorder to vpermit free inow and outow Vof the fluid therefrom as thevalve moves.

Also stop plates |09 and ||0 areprovided at the inner ,and .outer:limits respectively-.of the ytravel of the valve, plate IIO beingremovably held in place to permit of ready removal and replacement ofthe valve.

Theoperation of Vthis mechanism is as follows. In the position shown inFig. 3, land covers port |04 and hence the pump pressure from chamber 9|is not effective. However the tube |01 is openedto the space betweenlands |0| and |02, and the pressure of chamber 98 isftherefore effectivetherein. Because of the difference in the projected areas of the lands,there is a resultant force established tending to cause movement of thevalve member radially inwardly. The valve body itself is subject tocentrifugal force, and its weight is suitably selected to be responsiveto a predetermined speed condition. As the pumpcontinues to operate, thepressure within the discharge chamber 98 builds up, and if not requiredfor use, Areaches a maximum desired value. At this point, the forceacting upon the valve body I 00 is sufficient to overcome the eiect ofcentrifugal force thereon and results in initiating movement of thevalve body radially inwardly. As soon however as the valve begins tomove inwardly, the centrifugal force effective thereon decreases becauseof its lesser radial distance from the axis of rotation. As a result thevalve quickly is moved into its innermost position, and in .suchposition the land I0| uncovers the port |04 and permits fluid to flowtherethrough from pump chamberv 9| directly back to the reservoir. Thuswhile the pump continues to operate, it merely circulates the fluidsubstantially without pressure and hence performs only a very small andunobjectionable amount of work.

The pressure within the discharge chamber 98 is maintained meanwhile byreason of the closing of valve member 9b which thus functions as a checkvalve to retain the pressure in the system. Should operating fluid berequired, or upon such leakage taking place as to reduce the pressurewithin chamber 98, the pressure effective upon the diierential area ofvalve |00 becomes less than that necessary to retain it in its innerposition. At this time it begins to move outward1y,.and since thecentrifugal force increases with its greater radial distance from vtheaxis of rotation, it immediately moves to its outermost position,completely closing relief port |04, and providing for the continueddelivery of pressure fluid to the discharge chamber 98.

It will thus be seen` that the operation of the valve is unstable, andthat it necessarily adopts one or the other of its two extremepositions. It will also be noted that inasmuch as the valve body issubjected to greater centrifugal force at higher speeds, it-willautomatically provide for building up and maintaining a greater pressurewithin the discharge chamber' S8 at higher speed conditions. The actualspeeds at which the valve will function are suitably selected by varyingthe weight of the valve, and it will be seen that it can be readilyremoved and replaced by a valve of different weight as required. Furtherthe degree of pressure dro-p which will result in the outward movementof the valve body may be regulated by changing the relative diameters oflands IGI and |32, and by varying the degree of radial movement of thevalve.

In order to provide for delivery ofthe pressure fluid from dischargechamber 93, a pair of tubes |25 are provided which communicate with thatchamber and are located in the body of plate 50, being preferably castto form an integral unit therewith. These tubes lead arcuately around isopposed by means of compression spring |20 acting on the opposite sideof the piston, a suitable stop plate I2I being provided to limit theinner movement of the piston. In operation, the pistons are maintainedin a partially depressed condition rby reason of the development andmaintenance of the fluid pressure transmitted thereto by tubes ||5.lThey provide a storage space of substantial capacity in the aggregate,and thus tend to reduce fluctuation in the pressure within the tube,providing more uniform vpressure conditions for use. It will also beappreciated that they afford a source of pressure for return delivery tothe valve chamber to replace such leakage as may occur therein, andhence increase the periods between successive operations of the reliefvalve and pump mechanism as described above. As shown three of theaccumulators I |1 are provided in communication with each of the tubes||5. y

The pressure tube H5, as shown in Figs. 7 and 8, leads into the centralpart of a regulator valve chamber |25 carried on plate 50. The regulatorvalve body is shown at |26 and comprises lands |21, |28 and |29 spacedfrom each other by a portion of reduced diameter. Land |21 controls anoutlet port |30 while land |28 controls outlet port I3l. A pressureo-perating line |32 communicates with port |30 and a pressure operatingline |33 communicates with port |3I, line |32 being located radiallyinwardly of line |33. Pressure relief ports |25a open through thechamber |25 between the lands |28 and |29, and communicate with thereservoir. The valve body is also provided with a pin |35 at itsradially outer end and in the land |29 to .which is attached anoperating yoke |36 having threadedly received therein la lever arm |31.

Valve body |26 is mounted radially, and is directly subject to theaction of centrifugal force, acting upon the body itself. In order toovercome the tendency of centrifugal force to move the Aand hence aconstant opposing force is applied to the valve body for resisting theoutward movement thereof.

In order to provide for variation in the response of the regulatorvalve, a variable fulcrum is provided for the lever |31. For thispurpose a stud |45 is fastened to the valve casing, and projectstherefrom generally parallel with lever |31. A shoe |46 is slidablyadjustable along stud |45 and carries a roller |41 which rides upon thelever |31, forming a fulcrum therefor. It will be apparent that uponmovement of roller |41, the effeet of the spring force'as opposing thecentrifugal force acting on the valve body will be varied, since anychange in the position of the fulcrum roller will produce a greaterproportion of change in the lever arm of the spring than in the leverkventl axial vmovement thereof, these parts arm effective withrespectto-the -valve body. Aswill' be more-'completely-describedhereinafter',v

- movement ofthe rollertoward vtlle'valve body'ref sults in lesseningthe spring `force'eliective upony the same-thus causing the valve -bodyto movey outwardly 'to cause the application of fluid pressure in suchldirection aslto-bring about an increase-inthe pitchvangle of theblades;y speed then tends toi slowdown, and the centrifugalforce'effective uponthev valve body to oppose that of the spring islikewise reduced so that an equilibrium orbalance point is establishedata slower speed of rotation. The converse is equally true, movement ofthe fulcrfum' roller awayfrom the valve-body effecting an increase inthe effect of thespring force and hence resulting in inward movementofthe valve to cause application" of fluid pressure to effect a lowerpitchsetting ofthe blades. Therefis a consequent greater speed-of operation,which inturn producesan increased;y centrifugal force in Aorder to againreach a bal; anced condition of.l regulation at a new speed level.Y

It will likewisebe clear that movement of the. roller towardythe valvebody'sufliciently'to bring'` thel line yof action ofthe spring'forcedirectlyK towardv the roller; or to the right .thereofI as viewed inFig. 7,will result in the valve moving: to andremaining in its outerposition thus bring-- ingv about'` the maximum increase in the pitch oftheblades. This will provide'forthe adjustment thus taking axial: thrustin'- either direction.

The `forwardly projecting end of' shaft |66 is threaded vas shown in-|1| andis received within The.

oftheblades to-afully feathered position, where f accessiblefors-operation from. theaircraft. As`

mounted on sleeve |5|"carried by the adapter plate51 or` other suitablestationary part, and to be v.actuated either manually or under thecontrol of suitable instruments. -Thelevercarries' at'its lower. end atoothed sector' |53"which engages with4 the pinion |54 of a gearandpinion assemblyl rotatably'mounted'upon a. studshaft |55 and suitablyjournaled in the motor casing. The gear |56 `meshes with a ring 'gear|5T`mounted yfor rotation upon a stationary sleevey |58. projecting fromthe engine casingthe gearr being suitably, held therein by means ofvaplat'e |59 Aand snap ring |60. Meshi'nggwith.ringgear |51 ,area series.of operatingfpinions |61,A shownas comprising threepinions,each.mountedforrotationfin a. bracket |62'carriedby the adapterplate 51. The. pinions |6| are.'symmetricallylocated along theAperipheryy of ther shaft and .provide for rotating. shaftsy |63y whichextends through the casing, be-. ing providedwithsu-itable sealing means|64. Each shaftu |63 sv-.providedwitha tongue andv groove' connection|65..with a second lshaft |66r which is rotatably mountedv within the.stationary1 member 55,l theftorigue.k and groove;construction`rproviding for; the ready. separation of the-,two sha-ft,` sections from,each-other; duringl assembly.` 0r disassembly of the'device as 'hub`=|'4'is removedy or replacediuponwshaf't |21? -Shaft |66 `'extendsthrough member 55andintothe interiorof the reservoir. Atthe point whereit passes through.

the wall of member 55, itis Jforrnedwith a shoulder |68; and in orderto'provide forV takingl up axial thrust;A aenotched plate |69 isi boltedtothef a ringl sleeve'l12. Thesleeve is splined as shown at' |13`tothe'stationary sleeve 5| in such manner that upon-the rotation of thethree shafts |66; thesleeveis causedV to move axially, while being,restrained against lcircular movement. As will beapparent, this. axialmovement of sleeve |12 takesfplace inaccordance with the adjustingmovement of lever |50. i l

Apair'of llevers |15 are mountedwithin reservoir, conveniently throughtheprovision of lugs posite "sides and is caused vto move toward or awayfrom theregulator valve to vary the effective force 'of the spring,yand'the length' of the lever arms as previouslyfdescribed.

vIt will thus be apparent that with a fixed'setting ofthe fulcrumroller|41 the regulator will tend to maintaina balancedrv position such as tobring about constant speed Operation; and `upon the superiniposing of amanualor-other control Y to vary the position o'f the fulcrum, the Vregulator shown, a lever arm |50 is arranged tob'e rockably 'Y face ofmemberv asshowir'at: |10; Thegouter' face of vplateH 55 andl the/innerfacef of plate |69 1 thus serve to confine they shoulder `|68 and tolpref tendsv to regulate to av ,different predetermined position.` n 4 AA Y The manner 4inwhich th'epressure iiuid isfdistributed through. thetubes |32 and |33, in order to bring about respectively a decrease andan increase in the'pitch setting of theblades will now bedescribed. Asshown in Fig.` 8,5the two tubes y |32 and |33 are arrangedinfagenerallyconcentriclmannenveach makinga lcontinuous closed circuit'upon itself; Tube I 32 is provided' with a series of three openings|85, while tube |33 is provided with asimilar series of openings |86.

Each series istequidistantly arranged and the two series are arrangedlin staggered relation with respect to each'other. These openings |85 and|86 project through the ywall of platek 50, andare locatedimmediatelyadjacent the walls of bladeI socketsv 5J As shown injFifg. 10,r acorresponding series'of'openings |88 'isprovided at the same diameterand inithe` same'corresponding spacing as openings that is, onefor eachofthe threeA blade sockets. A- second series v'|89'is providedcorrespondingly arranged with respect to vopenings |86. This provides anopening |83v and an opening l89leading into each of the 'three bladefrom the opening |89I into a position removed from the axis ofthe blade.Thus uid may be introduced throughline |90 into the-central portion oftheblade socket and upwardly vthroughV passage |92 into the interior ofva 'sleeve member Tube |9| providesfor the introduction of. fluidthrough passages |96 and' |96' to thespaceA cxternalrofz thesleeve |95tand inwardly of the' actual wall of the blade root. Suitable packing I91 is provided for preventing the escape of uid from the space externalto sleeve |95 and a supplypassage for the fluid is formed therethrough;

Sleeve |95 is fastened to hub I4 by means of pins |98 so that it ismounted thereon and prevented from turning with respect thereto.l At itsouter end, the sleeve is provided with a packed joint 200 through whichthere slidably projects a hollow piston rod 20|. A piston 202 havingpredetermined mass is carried by the piston rod at its outer end and isarranged to operate in iiuid sealed relation within a cylinder 204. Thecylinder 204 is fastened to the blade I6 by means of pins 205 so thatupon rotation it will effect correspondingxotation of the blade. Thepiston is formed with an inwardly projecting sleeve 206, the inner faceof which is arranged to engage and slide over the outer face of thestationary sleeve |95. These two faces are provided with cooperatinghelical spline surfaces 201, so that upon radial movement of sleeve 206,it is also caused to rotate against the xed sleeve |95. Similarly theouter surface of sleeve 206 is arranged to engage and slide over theinner surface of cylinder 204 which is suitably offset to receive thesame, and these parts are provided with cooperating spiral splines 208so that radial movement of sleeve 206 imparts additional rotationalmovement to cylinder 204. Thus the movement of piston 202 effectsmovement of its sleeve 206, and that movement causes a resultant angularor rotational-movement of the cylinder 204 to take place, in accordancewith the sumof the angular movements produced by the two sets ofcooperating spline surfaces. The length of `the cooperating splinesurfaces and the pitch angles of the respective helixes are selected asdesired to give the proper degree of movement for adjusting the pitch ofthe blades from a low or negative pitch position, through the operatingrange to a high pitch or feathered position.` If desired the mechanismdisclosed in copending application Serial No. 279,530 now Patent2,307,101 may be utilized for this purpose. l

The blade I 6 is retained in its socket I5 by means of a collar 2|0threaded on to the root of the blade and engaging a series of stackedball bearings 2 I I which are held within the socket by an outerthreaded collar 2|2 suitably locked in place by a lock 2|3. The blade isadditionally guided for rotation upon its own axis by ball bearing 2|5,thereby providing an antifriction support for the blade upon the hub I4.In order to enclose the hub, an annular plate orcasting 2|6 is boltedagainst the hub, providing for retaining lubricant, etc. within thesame.

It will be apparent from the foregoing that introduction of pressureoperating fluid into the interior of sleeve |95 through the opening |92provides for the application of that fluid through the hollow piston rod20| to the outer surface of piston 202. Hence ,such application willforce the piston inwardly. The spline teeth 201 and 208 are so arrangedthat such inward movement of the piston produces a decrease in the pitchof the blades. Conversely when the pressure is supplied through port|3|, tube |33, openings |86, |89, and tube |9| to the outside of thesleeve 'I 95, it flows upwardly over the respective spline teeth 201 and208 to effect the lubrication thereof, and then into the space beneathpiston 202 with resultant outward movement thereof. Upon such movementthe patch of the blades is increased.

It will be understood that whengpressure is applied upon one side or inone direction, the pressure is simultaneously relieved upon the otherside of the piston, and the fluid in that part of the system allowed todischarge back into the reservoir by the uncovering of the correspondingport. For example when valve |26 moves outwardly tov supply pressurefluid to tube |33, land |21 moves to uncover port |30, and fluid fromtube |32 is then free to fiow through the open port and back into thereservoir. Each end of valve chamber |25 is open'and in communicationwith the reservoir for return discharge of fluid from either tube.

Each blade thus has its ownpressure actuating mechanismjand is arrangedto be operated through the positive application of hydraulic pressure ineach direction to effect both pitch increase and pitch decrease. Inorder to maintain uniform control over the position of all the blades,each blade is provided with a beveled gear sector 220 which meshes witha ring gear 22|,

suitably mounted upon ball bearing 222 carriedl by the forwardlyprojecting part 43 of hub I4. Thus gear 22| operates as a synchronizingmechanism to assure that the position of all the indi- `vidual blades inthe hub will be the same at all times.

As described in the above referred to application Serial No. 279,530,now Patent 2,307,101, this arrangement provides for substantiallybalancing the forces effective upon the blade within a predeterminedposition of normal flight settings. Certain forces acting upon the bladetend to cause decrease in the pitch thereof, but in the preferredarangement these forces are not relied upon to return the blades to alower pitch position. The

weight of piston 202 is preferably chosen so that the effect ofcentrifugal force thereon tending to move the piston outwardly and henceto increase the pitch of the blades is substantially balanced with theforces tending to cause decrease in the pitch of the blades, at apreselected point or range within the normal operating range of bladepositions. Positive application of pressure is utilized to overcome theinherent frictional forces present, and to adjust the pitch of theblades to a proper setting in both directions while provision is madefor assuring the blades remaining in a satisfactory operating positioneven in the event of complete failure of the uid pressure system and thecontrol mechanism.

The mechanism in the forward hub is in many respects the same as thatdescribed above. Except as otherwise indicated the elements of structurein the forward hub similar to those of the rear hub have been givenreference characters of the same order, but increased by 2003` Thus, thefront hub Acarries an annular plate 250 similar to plate 50 carried bythe rear hub. This plate is retained in position on hub 25 by means oflocking ring 25| threadedly received upon the h'ub. Bolts 252 removablyattach a covering or housing member 253 to the plate 250 formingtherewith areservoir for receiving a quantity of pressure operatingfluid. A sleeve member 255 is bolted to cover plate 2|6 rotatable withrear hub I4 and projects Within the reservoir of the front hub. It isformed with an axial portion 258 and with a radially extending cam 259.Such cam however differs from the stationary cam 59 in the rear hub inthat it is supported and carried by the rear hub assembly and hence isrotated in a direction opposite to that of the forward hub, producing arelative rotation between such parts of:v twiceA ther. individual.speed: As a'...result=,;` and.

ixr order:v tosecuref'similar'operation of; thipump. mechanism, cam'A259-: is: preferably.' formed with" only a single lobe thereon-"soathatthe same ratev of pump. .operation will be. secured.: iSe'ali'ngmeans- 7260' and.' 264 provide vfor enclosing.r the interior: of thelreservoir'. at the. adjacent" surfaces'vr of v'Iplate- 250= with' sleeveportion 258:,1 and-1 at theadjacent surfaces:I of'cover 2543'with'sleeve 255; thereby ypre'ventingiescape .off lubricant' therefrom.'

= shafeatr'is1etatauy mountedffwithm1-p1jate 21s and=extendstherethrougliewitha pinion'r3zl 8V upon its overh'anginggrendzwhichis'adaptedto mesh with gear `teeth 316. Preferably; three such 'shaftsare so positioned in uniformly spaced relation around' the peripheryeach carrying a pinion in driven relationwith gear teeth3l6, sorastosecure balanced 'operating' conditions.

`Shaft :ill-'basar tongue. andv groove connection.

shown at 319 with a. second shaft 32D'rnounted lwithinrthe ring-.1255,andf extending outwardly Also:A an air'fpressurefreleasing constructionsimi'- lar to that shown Aat 66, 61 inthe rear hub'is` preferablyprovided..y

Y The reservoirLwithin' the front hub likewise con'-y tains aipairyoff'pumps 271i; arranged in spaced' relation to. eachother;correspondingvalvecham;

ber's21l; and. a single pressure'i'elief mechanism 212, these partsbeing similar in'construction'and mode of operation tothecorrespon'ding'parts y'described abovedny theirear'hulb..y

The regulatorfvalve vbodyI` 3001 of fthe forward'y hubis;slidablymountedwithin cylinder 3M whichi is 'carriedibytheplate-2502": '.Th'e pressureffrom:

the pressure'lzsupply'ysystem .leads'into theacentrall port' 302 'andsupplieszpressure tinto. thenareabe tween'- the' two lands '.3031and:^30.`l.s 'ihesef'laruzisrcontrol loutlets 305l and v3(16.respectively .and pro"- vider` ferr' establishingv 4communieation from'the pressure `source to. operatingftubesfwfl' and' Staf respectively.In'this 'respect'l the. construction'is.:

- 4blades I6, ring lgear '22| willvbe correspondingly' the'ysameasfpreviously described, fthe.' supplyJo-f pressure uidbeingfriselectively:directed:to-:one: I

. lorthe 'other'oftheserpressuresupply lines; to-t'bef i` carriedintethe several blade "soekets. and.A tof. be

there supplied toene "-si'de'orj'th'e otherjofthe: individual. 'pistonsin the lbladesockets 'to effect the adjustment 'of the pitchA setting of'thebladesi` Itwill be understoodfthatf'asfrin .'.theiireari hub;``iii-troduction'of fluid-1 Dressureithrough: the radially inner 'tubeSllresu'lts inr.bringng' about ade'- creasein thev blade' 'pitchv while:introduction through'outer'ftubelBSY causes yincrease'. in'- the. Ditchoftloesevera'l'blades.A I n i 'i 'l However the control'and'cperatio'nof` regulator' valvev '300 fini the forwardf'huhare different:from

" withfthe' forwardfhub,

'therethrough'and'terminating in' a threaded portion.32-l withini thereservoir oftheA forward hub. Preferably the shaft` is yprovided withthe thrust n collar construction .described'above .in vconnectionwithzth'e shaft sections I\63-and:|64, providing for taking upaxia-l.thrust ladson the shaftwhile' permitting. readyl separation thereof,Yfor dismantling ofthe hub.. Agrooved ringf322i'is 'slid' ably mounted.upon'fsleeve 2 58'y andv threadedlyvy engaged by vthe several'.operating .shafts-32| to' be' moved:-axally. upon rotationthereof;r Thering has azperiphera'l. groove "323 within which* there is adaptedito'.ridev a follower shoes 324' rotatable ingfplacecin the pitch`Y an'glesetting of; the rear rotated; andl this. will ingturn effect therotation of theA shait'sections.y 32.!` 'to reffect ay correspondingadjustment intheposition of ring. 322 and ofv shoes 3241Ihus'fori-everypitch' angle `setting of the .rear propeller' blades;`there is'a' corresponding axial positioningof the; shoes 32:4, and they'rejspon'dz` byaxialiimovementzinf one 'direction or the' other to*eitherr increase or'fdecrease' in. the pitch of the rearblacles.'

` Referringz'to' Figs. 1K7v 'an'd 18;. thereis shown the i .ringl gear'330=which1istmounted .upon rollerlcearing33l for'rotation'.about"forward' hub 25. This vring gear'serves lthesame-.purpose aspreviously ldescribed gear-22| lin' the'r realrhub;` in synchroof-Ybeing `independently f controlled: 'in zresponseato'.

speed or manu'alwad-justment; the'iregulating ac-l tionv of valve30.0'is made dependent `upon'changes` inthe actual settingo'fIthebladesofthe rear hub; By'providingfanfelenrent Within the forward hubow-hichy.isi' adjustabler inqiaccorda-nce with, ory itri'esponsetochanges ini,thefsettinggof.the'blades'.Y of.v the rear: hub: theA forward. regulator'valve is' displacedfr'omr its 'neutralirpcsition 'and made to; respond'to such. changes rin'ithel rear blades,.there by,r controlling' theIsetting; 'of' the forward blades' impredetermined: relationr. withrespect'sthereto.'y

Arfollovw upgmechanismisl provided so= that 'whena' the properadjustment" has. taken place in'th'ejfor'- nizing' or correlatingtheadjusting'movements ofl the several blades in the forwardI hub, eachbladey having a sector meshing'iwith. the' vring-"gear and making itnecessary'that'all'of such blades'occupy the'- sameangular position. atall times. The bear'- ing' 33| isfretainedi'in place by means of ah'ousshown.. at `33?, andA4 with a. locking ring 334 threadtedffi'nto'fthe: hubi 25for"re'tainin'githe same in' po- Asition'. p A Inorder'to providefa' follow-up device respon-v siye'r: toI the" change'nin: position of "the forward b'la'rie'sithe ring'gear 330 is providedwith a forwardlyf'extending sleevexpjortion 340. which is Ward; blades'to= correspond lwith the change rwhich:v

has occurred.v in'- .the' :rear: blades, the regulator, valvewill. befrestored tov :neutral position', cutting 01T .supplyofzregulatin'ga'ilnidto. either side'-'of the?.

pistons.V Although thefyalvermay-be arrangedl'in a: radialvpositionzforypurposes of simplification. and standardizatiorrof.l parts'fin'jthe twohubs and isi .thus subject to centrifugal. force; that force is not'utilized in.' the-control of-its operation, Aits position.beinggdetermined inspthefy manner described regardlessof thecentrifugal-force'acting' thereon. For s this. purpose; sting; gear 1i 22 I 'fini the rear 'hubis provided' withfa forwardlyl extending'v ncylindrical part 3.-l'5 fuponirthe-internal face ofy which fare provideda:series-Sofi.gear.` teeth 3 I6. A1'

throatfof the bladesockets,l and out 'of'that areaA occupied' bygthefpreviously, described operating recessed as vshown at 34| to providefor' receiving camp'lates. 342' therein.' `T'hefcarn plates are l0-.c'atedi in spaced' relation. around 'the periphery of? .sleevev 34'fand.'inr'symmetrical relation at either.

side-of one;ofr.i1the blade sockets.` These cam platesf are removablyheldwithin' the sleeve rec'esses1334l .lbyimeansrof'sb'olts 343so\'thatif deelsi'red' each: onezcanifbezreadily' removed'. and: re-

l placed Acamz'sloti344 of. predetermined shape' is.4 providedwithinztthefplates 342,' and working within each such slotv is a camnger345( Fingers 345may be-"formed' as an' integral .part of 'operatingrrods .346'which' pass'fthrou'ghfrthe lower' walls at'eithersidof one'ofthe blade `sockets 26'being' guided thereby'vfor axial movement; theoperating` rods: extending: rearwardly in't'the'zone of the the.' ringitself being "rotatable with'the rearl'iu'b'.' f It willbezclearthat'upon: anyadjustment tak.-

and adjusting mechanism. The direction of the cam tracks 344 is suchthat upon increase of blade pitch, rods 346 are moved forwardly ortoward the forward end of the propeller, and vice versa. l

Rods 346 extend through plate 250 and into the reservoir where theyterminate in ball and socket joints 355. Connection is there made tofloating levers 35| which extend downwardly past the opposite sides ofring 322 and are attached to the shoes 324. The two levers 35| arepreferably joined together in an arcuate manner at theirA lower side,and connection is there made to a lug 35? having an elongated slot 353therein. A bell crank lever 355 is pivotally mounted at 355 and carriespin 351 at one end which is adapted to ride within the slot 353. At itsother end, the lever is formed with a bifurcated part 358 which engagesover pin 359, carried by the valve body 3D0. Thus upon pivotal movement,of the bell crank lever in one direction or the other away from itsneutral position, the valve body is caused to move inwardly or outwardlyto provide for supply of pressure from the pressure source to theindividual blade pistons for effecting selective adjustment in thesetting of the blades to effect increase or decrease of the pitchthereof.

In operation, upon a change taking place in the setting of -the bladesin the rear hub, a corresponding shift in the position of ring 322 takesplace as described. Assuming an increase in the pitch of the rear bladesto have taken place, ring 322 is moved axially toward the plate 250, i.e., toward the left as shown in Fig. 17 With rods 345 stationary, theshoes 324 move toward the forlward blade sockets and lever arms 35|pivot about the point 35|), causing a displacement of lug 352 and acorresponding rocking of bell crank lever 355. This movement displacesvalve body 30D from its neutral position, causing it to move outwardlyand supplying pressure fluid through line 339 and into theseveral bladepistons in the direction to cause increase of the pitch of the blades.As adjusting movement of the blades in the forward hub takes place, ringIgear 330 is caused to rotate, and the cam track 344 thus causes adisplacement of rods 346 to take place to the left as shown in Fig. 17,this displacement being in such direction as to shift the pivot points353 in the same direction as the shift imparted to ring 32|. The supplyof pressure fluid to the blades in the forward hub continues thereforeuntil such time as, with continued rotation of the blades towardincreased pitch position, the

pivots 35|) have traveled toward plate 250 to a position in which levers35| have returned the lug 352 to its original position. This occurs whenthe extent of movement of rods 346 bears the same ratio to the entirelength of levers 35| that the extent of movement imparted to ring 322and shoes 324 bears to the length of the portion of the levers inwardlyof the shoes. When such conditions have been reached, valve body 300 isren turned to neutral, and adjusting movement of the forward bladesceases. It will be clear that the cam 342 is made of proper shape andsuch as to produce the necessary extent of movement of pivots 35|).Further where the lead of` the cam is uniform, the forward blades willfollow in their mo-vement the adjustments which occur in the rear bladesassuming the same pitch positions throughout the entire range. In somecases it is found preferable to have a differential adjustment takeplace, with the pitch of the forward greater or less degree than that ofthe rear blades. In such case the cam track is suitably shaped toprovide whatever relation is desired between the two sets of bladesthroughout the entire range of adjustment thereof. For example the pitchof the forward blades may be made to vary from that of the rear bladesbya constant amount, such as a few degrees, or by a ratio, providing agreater diierential at higher blade angles. The accessibilityandreplaceability of the cam plate facilitates making changes in suchcondition as desired.

The reverse operations of 'course take place upon adjustment of therearl blade in the opposite direction, there being vcorrespondingbalance Ipoints for the follow-up rods 346 forl every setting of ring322 at which the valve body is restored to a neutral position. n

In actual operation, these adjusting movements occur quite rapidly sothat the forward blades begin to operate shortly after movement of therear blades has begun. As soon as the valve body has been displaced fromits neutral position, control iiud is supplied to the forward blades insuch direction as to bring about a corresponding change, and movementthereof follows immediately. In the case of an extensive adjustment ofthe rear blades, the movement of the forward blades takes placeconcurrently and with only a brief lag with respect thereto. Actualmovement of the bell crank lever andthe valve body therefore isrelatively small, being merely enough in one direction or the other fromneutral position to uncover and establish selective communication withthe proper pressure supply tube.

It will be apparent from the foregoing that the forward blade adjustingmechanism will operate to maintain the blades at the predetermined pitchposition corresponding to the particular setting of the rear blades.Thus assuming a change in the setting of the` forward blades, forexample, by reason of reduction of fluid pressure within the bladepistons, and under such operating conditions that the forces effectiveupon the blades would cause a reduction in the pitch thereof, suchmovement would rotate ring gear 330 and cause corresponding shifting ofrods 346. If the change was a decrease in pitch, rods 346 would movetoward the rear hub', and would pivot about shoes 324, resultingjnmovement of bell crank 355 and outwardly displacing valve -body 30|).This movement effects introduction of pressure fluid in the direction tocause increased pitch'bf the blades, thus correcting for the changewhich presumptively occurred, the supply of fluid continuing until thepitch of the blades has been restored to its predetermined value.Analysis will show that a similar corrective action occurs upon a changein the opposite direction, the systme thus effecting initial adjustmentof the forward blades to a predetermined 'pitch position correspondingto each pitch setting of the rear blades, and then providing formaintaining the forward blades in such predetermined position.

The principle of this control f. has been illusvtrated diagrammaticallyvin Figs. 21 through 24 in greatly simplified form in order to moreclearly show the functioning and operation thereof.

In this arrangement, the engine is indicated at' a, the drive shaft forthe rear hub at bl and for the forward hub at bb. The rear blade socketand hub are represented at c, including all of the elements within therectangular outline which are rotatable therewith. -Similarly theforwardv hub, 'blade socket and parts rotatable therewith point zz withthe valve body.

are ,shown r`within the left 'hand orfQrWard .IGC-i The. manual -orinstrument-controlledfadjust# ing vmechanism is shownatd, effectingadjustmentin the position of the slidable ringe through the toothedsector, ring gear, pinions,- and threadtangle,` the blade'. socket beingmarked cc.-

ed shafts as shown.v Pivotally mounted lever fl rotatable ywith the hubcarries .a shoeiwhich VVruns in', ring e, and is rockedv`therebyto'clfiangejtlle position; of fulcrurn roller g at itsopposite-end,A Movement of roller g changesg'the eiectivevfforce Vofspring hwhich isppposed tothe centrifugal force acting on regulatorvalve body i,4 n Fluid pressure is developedvby'puvmpf-zj, rotatablewith the hub and actuated byr contactwith non-rotatingcam 1c, and issupplied-to 1;lo efregllv later valve, i.r

ncause pitch adjusting movement; of the indirv vidual blade-upon travelof the pistoni.;l -With tends to constantly assume a position .wheresucnforces; are in balance, being displacedfrom that position upon adeparture of ther-speed of rota-v tion of ythe propeller lfrom thepredetermined value, and upon vsuch displacement ,causinga changein thepitch or lthe blades :intheproper sensato .restore such speed condition.Upon/tad,-

Valve'i controls-the application y of suchfpressure to one sideortheotherwof the blade adjusting piston Z-withingbladesocket Anabutmentm and splinel connection vshovvn-.at e

- maar l '11n Fia 23, as a result yof, an adjustment move,- ment havingtaken place inthe rear hub`, ring ee has moved and the shoe ov is jno`longer in its original position but has moved to a nevv position l v'v.Prior to-'movem'ent of the forward blades',

follow-up rod ss has not moved,'and hence point it has not moved. Leverluul is therefore caused to pivot about point tft thereby causing theendww of y -thebellcrank to Inoveltoea position wwf ..Whichfin turn hasmoved the point eatoneW-positionz'e. I

This ,results in displacement ofthev valvefbody; f

causing .the supply lof* pressurevv fluid te Ione side ofthe-.piston ZZ;,"Asth'efpiston' moves in response'to thatA pressure application,thefollovvrup -rod-ssislilrewise eausdto move, and continues tomoVewpOint ttv tornew position tt'.. When it reaches suchpositiontt,l`(shoe' vv Aremaining at ov') the lever uu is swungftorbringpoint vww 4lever d inany fixed position, thecentrifugalfforce actingupon valve body i is opposedby anionstantv moment of force produced byspring blandv hence back to the original Vww position;A thus restoringthe bell. crank :m: to its original or yneutralposi-r tion.` With vthebell crankjthus restoredlto .its original pos'ition,.point aa has beenyrestored, and thevfalve bodyhas been returned toits neutral positionWhere j further v supply kof pressure fluid is cut offl- The'pitch vofthe forward blades lis y thus maintained at all times'inl'close'correlation Withthat ofy theel-rear blades.

V It is believedthat ,this win'nake naar the' rmanner of operation tof;the device", it being clear that upon an opposite movement of the bladeswithinthe rear hub, the oppositesequence of .op-l

Y erations takes place inthe forward hub,.the posi;

justment of lever 1d, l,the effectofthe spring `force l ischanged,and-thus. a new Speedfconditipn is selected `at which the centrifugal,forceonf-the valvefbody `will kbe inbalancer-With the" applied springforce, the valve being displaced from neui tral to'produce'such changeinbladelpitchffas l will bring about suchspeed change.

, AThe ring gear` o 'correlates theaction 4,o e rear bladesthrough'beveled gear sectors p carried thereby` and ,provides forladjusting the position of ring ee in the forward hub in.accordancevvith the setting of the blades in the rear-hubA through i theprovision of fthe, internal teethlonrinug gear.

0,' pinions and threaded shafts,asf shown5.-

' Pressure is developedin'thefgryvard hubby pump. means 7'7" rotatablewith thefforward hub Y and. operating against cam kk carriedbythe rearhub and hence rotating in the .opposite direction.

Suchpressure is supplied tov'alve'nii*from which it-fmay be applied tothe adjusting piston -lZ in the forward blade socketl ccunderthecontrol.of

the valve. The abutment mm clauses movement of; pistonjllrto effecttwisting of the blades k,in-the` forwardy hub, through spline`connection there slidably operatesfollowujp redes.: yllt terminates atpoint tt, Wherel it is connectedftothe upper end of ythe leveru-u, towhich is connected atan intermediate point the shoes' vowhichrideWithin` the ring ec. At its lower end,the point ww, the leverisconnected to bell crankmz piuotally mounted atv .yy and lhavingconnection at Fig. 22v .is a diagrammatic .represenaticn y.of a

tion ofthe blades of vthe forward hubthus being made to followv andbedependent upon those'of the rearhub. Asdescribedabove', the pitchangle l settings ofthe forward blades may bemadelto follow and,correspond precisely withthosefoflthe i rear blade,for toincreaseordecreasernore rapidly than-those'. of the rear hub where adifferential isdened in the lappended claims.v

V,lftinggear oo actuated by sectors pp rotatable -r with the blades isprovided with acam plategq' having a cam groove rrtherein within which 4.1; dual rotation 'propeller of the. character described'adapted to' bedriven yfrom a pair of oppositelyrotating drive shafts comprising vapair of hubs respectively .associatedin driven relation with vsaid driveshafts and each provided With, a plurality of I .blade sockets,.propellerfblades ad,- justably mounted inl eachof said sockets, theblades of onehubbeing lof opposite pitch to those vof the otherhubgfluidpressure actuating means in each of said sockets for eiecting adjustmentf of said blades to var ythe: pitch thereof, separate normal or balancedpo'sitionof` thevpartsl` yy-n this position lever uu lis in 'alignmentwith the'` one v arm orfbell crank lever ma: and henoelthe bell crankoccupies its neutralpositiomand-through connection zz causesvalve ii tooccupy tsineutral position lin which :no nuid is supplied 1 -tol eitherside of lvthe operating piston-ll; j

fluid pressuredeveloping means in each vhub 'to supply-fluid ,underpressure vto said actuating means Vvvithin that hub, and means withineach hub for controlling the application of the fluid pressurev to theassociated actuating meanslto effect adjustment of the pitehse'tting` ofthe blades thereof the eontrfolling meansy Within onehub actinginresponse to changes in actuallsettinglfy theA blades ofthe other hub. i

2. A dual vrotation Propeller of `the y character described adapted tobedrivenfrom a pair ofi-op,-

placedftofs'ecure variation inthe operating conf v departing from thescopeof the invention' which positelyrotating drive shafts comprising apair.

of hubs respectively associated in driven relation with said driveshafts and each provided with a plurality of blade sockets, propellerblades adjustably mounted in each of said sockets, the blades of one hubbeing of opposite pitch to those of the other hub,'fluid pressureactuating means in each of said sockets for effecting adjustment of saidblades to vary the pitch thereof, separate liuid pressure developingmeans in each hub to supply fluid under pressure`to said actuating meanswithin thathub, means Within each hub for ycontrolling the applicationof the fluid pressure to the associated actuating means to effectothersad hub dependent upon the position of the blades in said firstmentioned hub for controlling the application of the vpower developingmeans of said other-hub to the power actuated means thereof to' effectva corresponding change in the i pitch setting of the blades of saidother hub.

blades of one hub being of opposite pitch to those means within thathub, means within each hub for controlling the application of the uidpressure to the associated actuating means to effect adjustment of thepitch setting of the blades thereof, speed responsive means in one ofsaid hubs for regulating the controlling means in that hub to ,adjustthesetting of its said blades to maintain Ya constant .speed condition,andmeans in the other of said hubs for effecting a correspondingadjustment in the regulation of its said controlling means.

4. A dual rotation propeller hub adapted to be driven from 'a pair ofoppositely rotating drive shafts comprising a pair of hubs eachassociated in driven relation with one cf said drive shafts and having aplurality of blade sockets for adjustably receiving blades therein withthe blades of one hubbeing of opposite pitch to those of the other,power actuated means in each hub for adjusting the pitch of the bladesthereof, means in each hub for developing power to effect actuation ofsaid power actuated means, and control means inr each hub forcontrolling the application of said developed power to maintain apredeter-K` mined position of said blades, and means for correlating theaction of the control means in said two hubs to cause both'sets ofblades to occupy a corresponding pitch position to each other.l

5. A dual rotation propeller adapted to' be driven from a pair ofoppositelyrotating drive shafts comprising a pair of hubs eachassociated in driven relation with one of said drivevshafts and having aplurality of blade sockets, blades adjustably mounted in said bladesockets with those of one hub being of opposite pitch to those of theother, power actuated means in each hub for adjusting thepitch of theblades, means in each hub` for developing powerlto effect actuation ofsaid `power actuated means, independent control means in one of saidhubs for controlling the applicationof the power developing meansthereof to the power actuated means thereof to effect adjustment of thepitch setting of the blades of that hub, and control means in the 6. Adual rotation propeller adapted to be driven from a ypairof oppositelyrotating'v drive shafts comprising a pair of hubs each associated indriven vrelation with one4 of said drive shafts and having a pluralityof blade sockets, blades adjustably mounted .in saidblade sockets withthose of one hub being of opposite pitch to those of theother, poweractuated means in each hub for adjusting the pitch of the bladesthereof, means' in eachhub for developing power to effect actuation ofsaid power actuated means, speed responsive means for controlling theapplication of power developed in one of said hubs to adjust theposition ofthe blades of that hub to maintain a predetermined speedcondition, and control means associated with said other lhub forcontrolling the applicationl of power'developedin said other hub-tocause the blades of the latter hub to assume a 'position correspondingwith those of the first mentioned hub to maintain a constant speed andbalanced thrust condition of the entire propeller.

7. A dual 4rotation propeller adapted to be driven from a pairofoppositely rotating drive shafts comprising a pair of hubs eachassociated in driven relation with one of said drive shafts and having aplurality of blade sockets, blades adjustably ymount'edin said bladesockets with those of one hub being of opposite pitch to those of theother, fiuid pressure actuated means in each hub for adjusting vthepitch of the blades thereof, a source of fluid pressure in each hub forapplication to said ypressure actuated means to effect adjustment of thepitch of the blades, speed responsive means within one of said hubs forcontrolling'the application of said pressure source to adjust theposition of the `blades of that hub to maintain a predetermined speedcondition, and control means associated with the other said hubandresponsive to the position of the blades in said first-mentioned hubfor controlling the application of the; pressure source of said otherhub to the pressure actuated means thereof to cause the blades thereofto assume a position corresponding with those of said first-mentionedhub.

y8. `A dual rotation propeller adapted to be drivenfrom a lpairofoppositely rotating drive shafts comprising a pair of hubs eachassociated in driven relation with one of said drive shafts and having aplurality of blade sockets, blades adjustably mounted in said'bladesockets with those of one hub beingvof opposite pitch to those of theother, fluidpressure actuated means in each hub for adjusting the pitchof the blades thereof, aA source of fluid pressure in each hub fora-pplicationfto said pressure actuated means to effect adjustment of thepitch of the blades, speed responsivev means within one of said hubs forcontrolling the application of said pressure source to adjust theposition ofthe blades of that hub to maintain a predeterminedspeedcondition, independent control means associated with said one hub foradjusting said speed responsive means to vselectively vary saidpredetermined speed to which said propeller is regulated, and controlmeans associated with the other said hub and responsive tothe positionof the blades in said first-mentioned" hub for controlling theapplication of the pressure source of said other agsemcu hub.mmepressure .actuated means. thereof; te 1 cause the blades thereof to.assume a position corresponding witlrthose of said mst-mentioned v hub.1

thosey of` cnehub: being off opposite pitch to those ofthe other, fluidpressureactuated meansin eachhub forl positively adjusting*y theApitchof the blades thereof in both pitch increasing and decreasingadjustments, meansin eachhub for de' veloping fluid pressureto effectactuation of said passingV the `fluid pressure actuatedmeanspindependent control means in one of said hubs for controlling theyapplication of said fluid pressure to said pressure actuated means tovadjust .the blades of said hub to a-predeter'mined pitch position, meansinthe otherrsaid 'huby dependent upon the actual position of the bladesoi"` said 'rst mentioned hub for i l rotatable With each ofrsaid hubs,pump mechay nismfca'rried by each hub and communicating with-saidfrespective reservoirs, a stationary memcontrolling the application.of the iiuid pressure within said other hub to the pressure actuatedmeans thereof tomaintain a corresponding posi-` i hubl `to vary by aYpredetermined-differential from lthe pitch setting tioned hub. y

1 10. A dual rotation propeller adaptedVto"bev driven' froml a pair ofioppositelyfrotating"drive shafts comprising a pair of hubs eachassociated "2'.

with forireceiving a quantity-of operating iluid` therein, means within.each reservoir [for fsubjecting the fluid therein to pressure to provideindependent sources'of pressure actuating fluid,A

fluid pressure actuated means in veach blade socket Vforeffecting/adjustment ofthe pitchl setting vof the blades therein,control meansin each hub for separately controlling "the application ofrthe fluid pressure sources thereof to said' pressure tion ofthe bladesof that hub'in relation tothose yof said first mentioned hub, andymeansv for caus' Y ing the pitch setting of the bladesoi said other oflthose' of said first' men- 1 misnomer ,the -prepeuerfer. subjecting-.th're'- spective bodies ofv fluid topressure,-pressure rev vceivingmeansfor receiving the fluidv discharged from seidl'pump means, randmeans for Vlimiting the action yofsaid pump, means upontheestablishxnent of. a predetermined pressure condition" within saidreceiving means including valve members subject to centrifugal forceupon rotation of saidhubs,v means for supplying` fluid pressure fromsaid receiving means to said valve. means to move said valvesagainstthey action of centrifugal force -whenthe pressure in said receiving.means reaches said predetermined amount, and a ybye-pass.. associated'with each said pump means 'and'.openedby movement of said valve .forby# ,fromxsaid pump back to said reservoir. e l y 12. Aadualrotatlonpropeller ofthe character described comprising'a'p'air of drive shaftsrotate? ing` in opposite directions, hubs positioned ron each driveshaftin tandem relation to each other,

a.. plurality". of -hydraulically adjustable blades y carried' byfeach'hub, a fluid-containing reservoir b'er operable uponfthe pump,mechanismV offth'e rearxhub to provide for actuation thereof to sub-Aject'the kiluid in the reservoir ofthe rear hub f;- to`pressure,.amember carried by the` rear hub .and operable `upon the pump mechanismfof the forward hub to provide for actuation thereof to subject: theiluid'in thereservoir of the forward hub .to pressure, means Within eachhub' for lcon#- trolling theapplicationjof fluid vpressure to therespective hydraulically adjustable A blades, and

:neansresponding to the changes in actual set'- 'v ting @fk-the' @bladesef yene hub fory initiating change in the controlling means for theother hubft'oeifect va llikey change of blade setting.

1f13; A d uai 'rotation prepener of 'the character i 'described'whichcomprises a pair of hubs adapted to be received intandem Yrelationupon oppositely rotating drive shafts, adjustable pitchy blades actuatedmeans, speedresponsivemeans in one of said hubs for regula-tingr vtheoperation'of the .i

associated controlmeans therein,y and means in the other of saidhu'bsand responsive to the actual setting" ofthe blades in lsaidlfirst-men;`

tioned hubfor regulating the'action of its said associatedcontrol meansto thereby eiiectfa Acor-- responding pitch settingof the bladesv ofboth oi said hubs. e l. 11. A dual rotation propeller hub :mechanism ofthe character described comprising a pair of adjustably rsupportthefpropeller blades therein;r` vseparatev fluid pressure distributingmeans withinr each hub for effecting adjustment of the pitchofthe/blades of that hub,'.liousings carried byV eachy hub 'and forming`separate vreservoirs `therew1th for receiving a body'of pressure:actuating fluid, means extending fromjone housing into' the otherthousing for transmitting the adjusting vof pitch.

mountedupon said'y respective*` hubs, iluidpres; "surefresponsive'meansfori effecting pitch adjust- Ument of said blades'uid pressure means forsup.

'p'lyi-ng fluidunderpressurel toI effect. actuation of `lsa'i'dpressure" responsive means, independent control means for oneof saidhubs for controlling fthe-'supply loi pressure uid toa'djust the pitch yfof'tnegblades "orti-iat hub te a predetermined position,-andjcontr'ol'nieans for the other "said eo i described yvvliichycomprisesvv a pair of "hubs .adapted 'meansifor synchronizing theadjustingfoperation `ofthe .blades offene hubfwith the blades'fof "the.other'hub, iluidpressure means for supplying 7'0.

ofsaildf'rst'hubfor,controlling 'the supplyof pressureffluidjtoadjust-theA pitch of the 'blades' 'ofgfsaid `other hub in substantiallysynchronized relation with the pitch Aof the blades of said `rst'mentionedhub.l f Y.

14. A dujai rotation prepeuer ef; .the character to be received in`vtandem relation lupon oppo-L sitely rota-ting',f drive v`4shafts;adjustable jpitch bladesniounted @upon saidfrespectivehubs, iluid.pressurerespon'sive means associated with leach blade kfor'efreetingpiteh' adjustment thereof;

fluid',-.under` pressure to veffect actuation oi' `ysaid pressure'responsive means, independent control n ieans-forfone! of said hubs forcontrolling 'the `of'blades lof one hubto the iluid'pressure Ydis-ytributin'g means of the ether-hub; means within e each hub including`pump means operable upon supply of. pressure viiuidto adjust the pitchkof the bladeseof that hub 'to a predetermined posi- `tiornsmeans#forinitatinigthe supply ofl'pressuw `1 uid tov the `pressure responsivemeans ofvsaid other hub in accordance with a change in the setting oftheblades of said rst mentioned hub, and means for terminating said supplyof pressure` fluid to the pressure responsive means of said Iother hubwhen the blades of said other hub have been adjusted to a positioncorresponding with. that `of said first mentioned hub. f

15. `A dual rotation propeller of the character described adapted to bedrivenfrom oppositely rotating drive shafts comprising a pair of hubsadapted to be mounted in tandem `relation upon said drive shafts andeach provided with a plurality of blade sockets, propeller bladesadjustably mounted in` each of said sockets, the blades of one hubbeing.4 of opposite pitch to those of the other hub, fluid pressureactuating means in each of said socketsfor effectingadjustment of 'saidbladesv to vary the pitch thereof,'separate just the setting of its saidblades to maintain a constant speed condition, and means in the other ofsaid hubs for effecting actuation of Said` control means in said otherhub away from its neutral position upon change of pitch of theblades ofsaid first mentioned hub, and follow-up means responsive to the changeof pitch of the blades of said other hub to a position corresponding tothat'of theblades of said rst mentioned hub for restoring said controlmeans in said other hub toits neutral position.

16. A dual rotation propeller of the character `described adapted to bedrivenfrom oppositely rotating drivefshafts comprising a pair of hubsadapted to be mounted in tandem relation upon said drive shafts and eachprovided witha plurality of blade sockets, propeller blades adjustablymounted in each of said sockets, the blades of -one hub being ofopposite pitch to those of the `other hub, iiuid pressure actuatingmeans ineach of said sockets for effecting positive adjusting movementof said blades in each direction to vary the pitch thereof, separatefluid pressure developing means in each hub `to supply fluid underpressure selectively to said actuating means within that hub foreffecting pitchincrease or decrease, control means within each hubadjustablevin each direction away fromv a neutral position forcontrolling the application lof the 4fluid pressure to the associatedactuating means to effect adjustment of the pitch setting Ofthebladesthereonspeedresponsive means in one of said hubs for regulating thecontrolling means in that Ihub to adjust the setting of itsforrestoring' the said displaced `vcontrol means to neutral positionwhen thev blades of said other hubhaVe been changed in the same senseand to acorresponding position.

17. vA dual rotation propeller of the character rotating drive shaftscomprisingga'palr of hubs adapted to be mounted in tandem relation uponsaid drive shafts and eachprovided with a plurality of blade sockets,propeller blades adjustan pressure to the associatedI actuating means toeffect 'adjustmentr of the pitch setting of the blades thereof, speedresponsive'means in one of said hubs for regulating-the controllingmeans in that hub to adjust the setting of its said blades to maintain aconstant speed'condition, means in the other 'of said hubs responsive toa change of position'of the bladesofsaid first mentioned hub foreffecting displacement vof the control means of said other hub' awayfrom its neutral position in a sense corresponding to the directionofsaid change ofl position, means for restoring the `said displacedcontrol means to neutral position when the bladesof said other hub havebeen n changed in the same sense and to a corresponda ing position andremovable and replaceable means associated with the control' meansofsaid other l described adapted lto be driven from :oppositely 76 hubfor predetermining the relative settings between said bladesincorresponding positions.

18. A dual rotation propeller of the character l described adapted to bedriven'from oppositely rotating .drive shafts "comprising a, pair ofhubs adapted to be mounted in tandem relation upon lsaid drive shafts,propeller blades adjustably carried by each of `said hubs, the blades ofone hub b'einglof opposite pitch to those of the other hub, fluidpressure actuatingmeans in each of said hubs for effecting adjustment ofsaid blades to f vary thepitch thereof, separate fluid pressuredeveloping means in each hub to supply fluid under pressure to saidactuating means within that hub, means within each hub for controlling'the application of-the fluid pressure to the actuating means of thathub to effect adjustment 'of the pitch setting of the blades thereof,independent means in one of said hubs for regulating the controllingmeans of .that hubto adjust the setting ofits said blades to apredetermined position, a member in said other hub responsive to theposition of the blades of said first mentioned hub, a second member insaid other hub responsive to the positionl of the blades of that hub,and

. means responsive to the position of said two members for regulatingthe Vaction of the controlling means of said `other hub to'provide formaintain? ing a predetermined relation between the setting of the bladesof said two hubs.l i j 1'9. A dual rotation lpropeller of the characterdescribed adapted to Abe driven from oppositely rotating drive shaftscomprising a pair of hubs adapted to be mounted in tandem relation uponsaid drive shafts, propeller blades adjustably carried byeach of saidhubs, the blades of one hub being of opposite pitch to those of theother hub, duid pressure actuating means in each of said hubs foreffecting adjustment of-said blades to vary the pitch thereof, separatefluid pressure developing ymeans inr each hub to supply fluid underpressure tofsaid actuating means within that hub,

